The Result and Operation of Casing Aphid Bags on the Tree Branch

The aphids cased in the bag can reproduce twice in three kinds of form without eating any food.The bags with holes are put on to the tree (of Rhus chinensis ) when the fundatrices emerge,the period of development of the aphid in the bag lasts from 21～48 d under the condition of house temperature.One of the main cause for the death of the aphid in the bag is squeezing and folding.The best time to hang the bags is within three days from the beginning of the emergence of the fundatrix.The result of the casing at the time when the 4th～6th juvenile leaves of host tree unfold are better than any other time.The emergence of the fundatrices may be controlled through adjusting the storage temperature.The stronger the branch,the more galls are made on more leaves.To hang the bags twice on one host tree can increase the number of the leaves with galls.